Organic Light Emitting Diode (OLED) has a self-luminous feature, and uses a very thin organic material coating layer and a glass substrate. When currents pass through it, organic material will be luminous. Furthermore, the visible angle of an OLED screen is large and OLEDs significantly save power, thus OLEDs is more and more widely applied at present.
The core element of an OLED display apparatus is an OLED display panel, usually comprising: a Thin Film Transistor (TFT) array substrate and layers in turn disposed on the TFT substrate, which are an anode layer, a pixel definition layer, a first common layer for transmitting holes, an active layer, a second common layer for transmitting electrons and a cathode layer. The operating mechanism of an OLED display panel is the fact that the holes are transmitted to the active layer via the first common layer, and the electrons are transmitted to the active layer via the second common layer, then they recombines at the active layer to emit light.
For implementing full-color of an OLED display apparatus, one way is through the stack of White Organic Light Emitting Diodes (WOLEDs) and Color Filters (CFs). Wherein, high resolution of an OLED display could be accomplished without requiring accurate mask process in stack structure of WOLEDs and CFs, which is wider one of applications. Pixels of WOLEDs products consist of red, green, blue and white pixels, wherein red, green and blue light are emitted from red, green, and blue pixels by means of white light from WOLED devices passing through red, green, blue filters. Therefore, when there is a requirement of white light in this kind of product, white light pixels is lighting. The color point for a white pixel of WOLED is actually not the target white point appeared on a display panel, generally, WOLED light is hardly the same as the standard of white point in products. Therefore, it is required that one or two kinds of color sub-pixels emit corresponding light with specific ratio to combine with light from white pixels, so as to gain the white point of products (chromaticity coordinate of the white image).
A Y value of chromaticity coordinate is large for the white light with more components of yellow light emitted directly from WOLED devices, which needs higher brightness monochromatic light (e.g., blue light and red light, or blue light and green light) when color matching of white image is proceeding, accordingly the life of devices is reduced.